Description: Thallus cartilaginous, somewhat crispate, 2 to 40 cm tall, composed by one or several erect axes, terete or compressed, distichously, plumously or irregularly branched, red to deep purple, although in some species it can be blackish. Erect axes arise from cylindrical or compressed, branched or unbranched creeping axes with numerous short haptera extending as individual axes or forming massive disc-like holdfasts. Plants sometimes occur in mats of algal turf with extensive basal parts or in more discrete clamps. The erect fronds can be cylindrical at the base, subcylindrical above and frequently compressed at their apical ends. The cortex has several rows of pigmented cells, the smaller usually toward the outside, mostly 2-15 µm diam. On surface view they may have regular or irregular arrangement. The medullary cells are generally rounded in cross section, up to 30 µm diameter, colourless, compacted or loosely appressed. Elongated, colourless cells, known as rhizines, rhizoidal filaments or hyphae, are thick-walled, up to 5 µm diameter and 200 µm long,located in the medullary and/or cortical tissue, sometimes varying in number and position within species. The tetrasporangia in the sori occupy the entire, somewhat expanded or broadly rounded tips of lateral branches or main axes. Fertile branches can be simple or pinnately compound, somewhat twisted and densely congested They often have sterile margins. Tetrasporangia are cruciately divided, up to 35 µm in diameter, and arranged with or without order in the sori. The carpogonial filament is unicellular, fusing with adjacent cells after fertilization. The cystocarp protrudes equally on both surfaces of the branch, usually with one or, more rarely, several openings on each surface of the frond. Occasionally, two cystocarpic cavities coalesce laterally, forming enlarged cystocarps of up to 1 mm long.

Information contributed by: B. Santelices; modified by M.D. Guiry.
The most recent alteration to this page was made on 20 Jan 2017 by M.D. Guiry.

Comments: An intertidal to deep subtidal genus of cold to tropical waters worldwide. Geographically the most widespread genus in the Gelidiaceae. Seemingly absent from artic and subantarctic waters.

Numbers of names and species: There are 240 species names in the database at present, as well as 77 infraspecific names. Of the species names, 140 have been flagged as accepted taxonomically on the basis of the listed literature under the species name. In some instances, opinions on taxonomic validity differ from author to author and users are encouraged to form their own opinion. AlgaeBase is a work in progress and should not be regarded as a definitive source only as a guide to the literature..

Names: ('C' indicates a name that is accepted taxonomically; 'S' a homotypic or heterotypic synonym; 'U' indicates a name of uncertain taxonomic status, but which has been subjected to some verification nomenclaturally; 'P' indicates a preliminary AlgaeBase entry that has not been subjected to any kind of verification. For more information on a species click on it to activate a link to the Species database):

Verification of data
Users are responsible for verifying the accuracy of information before use, as noted on the website Content page.

Contributors
Some of the descriptions included in AlgaeBase were originally from the unpublished Encyclopedia of Algal Genera,
organised in the 1990s by Dr Bruce Parker on behalf of the Phycological Society of America (PSA)
and intended to be published in CD format.
These AlgaeBase descriptions are now being continually updated, and each current contributor is identified above.
The PSA and AlgaeBase warmly acknowledge the generosity of all past and present contributors and particularly the work of Dr Parker.